Search for Polycyclic Aromatic Hydrocarbons in the Outflows from Dust-Producing Wolf-Rayet Stars

Abstract

A combined mid-IR spectrum of five colliding-wind, massive, dust-producing Population I Wolf-Rayet (WR) binaries shows a wealth of absorption and emission details coming from the circumstellar dust envelopes, as well as from the interstellar medium. The prominent absorption features may arise from a mix of interstellar carbonaceous grains formed in high- (e.g., 3.4, 6.8, 7.2 $\mu$m) and low-temperature (3.3, 6.9, 9.3 $\mu$m) environments. The broad emission complexes around $\sim$6.5, 8.0 and 8.8 $\mu$m could arise from ionized, small polycyclic aromatic hydrocarbon (PAH) clusters and/or amorphous carbonaceous grains. As such these PAH emissions may represent the long sought after precursors of amorphous Carbon dust. We also detect a strong $\sim$10.0 $\mu$m emission in the spectra of WR48a and WR112, that we tentatively link to ionized PAHs. Upon examining the available archival spectra of prodigious individual WR dust sources, we notice a surprising lack of 7.7 $\mu$m PAH band in the spectrum of the binary WR19, in contrast to the apparent strength of the 11.2, 12.7 and 16.4 $\mu$m PAH features. Strong PAH emissions are also detected in the $\lambda >$10 $\mu$m spectrum of another dust-producing system, WR118, pointing to the presence of large, neutral, presumably interstellar PAH molecules towards WR19 and WR118.

Accepted for publication in Monthly Notices of the Royal Astronomical Society, Main Journal; 14pp., 12 figures

References in corpus (30)

• Infrared Emission from Interstellar Dust. IV. The Silicate-Graphite-PAH Model in the Post-Spitzer Era
• Physical Properties of Wolf-Rayet Stars
• A dusty, normal galaxy in the epoch of reionization
• The c2d Spitzer spectroscopic survey of ices around low-mass young stellar objects II: CO2
• Variations of the Mid-IR Aromatic Features Inside and Among Galaxies
• The Behavior of the Aromatic Features in M101 HII Regions: Evidence for Dust Processing
• Stellar Evolutionary Effects on the Abundances of PAH and SN-Condensed Dust in Galaxies
• The Galactic WC stars: Stellar parameters from spectral analyses indicate a new evolutionary sequence
• The unusual hydrocarbon emission from the early carbon star HD 100764: The connection between aromatics and aliphatics
• The dust condensation sequence in red super-giant stars
• Mapping PAH sizes in NGC 7023 with SOFIA
• Nuclear 11.3$\mu$m PAH emission in local active galactic nuclei
• Mid-Infrared Properties of Luminous Infrared Galaxies II: Probing the Dust and Gas Physics of the GOALS Sample
• Dust Attenuation in High Redshift Galaxies -- 'Diamonds in the Sky'
• The Fate of the First Galaxies. III. Properties of Primordial Dwarf Galaxies and their Impact on the Intergalactic Medium
• Star Formation Rates from [CII] 158 um and Mid Infrared Emission Lines for Starbursts and AGN
• Spitzer IRS Observations of the Galactic Center: Shocked Gas in the Radio Arc Bubble
• Pinwheels in the Quintuplet Cluster
• A Clumping Independent Diagnostic of Stellar Mass-loss Rates: Rapid Clump Destruction in Adiabatic Colliding Winds
• Dust formation, evolution, and obscuration effects in the very high-redshift universe
• A mid-infrared view of the inner parsecs of the Seyfert galaxy Mrk 1066 using CanariCam/GTC
• The Keck Aperture Masking Experiment: Near-Infrared Sizes of Dusty Wolf-Rayet Stars
• Random mixtures of polycyclic aromatic hydrocarbon spectra match interstellar infrared emission
• Circumstellar discs in Galactic centre clusters: Disc-bearing B-type stars in the Quintuplet and Arches clusters
• The mid-infrared appearance of the Galactic Mini-Starburst W49A
• Nature Versus Nurture: Luminous Blue Variable Nebulae in and near Massive Stellar Clusters at the Galactic Center
• Quantifying the Heating Sources for Mid-infrared Dust Emissions in Galaxies: The Case of M 81
• Dust composition and mass-loss return from the luminous blue variable R71 in the LMC
• Stagnant Shells in the Vicinity of the Dusty Wolf-Rayet-OB Binary WR 112
• ISO observations of the Wolf-Rayet galaxies NGC 5430, NGC 6764, Mrk 309 and VII Zw 19

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• Revisiting the Impact of Dust Production from Carbon-Rich Wolf-Rayet Binaries
• Supernova 2014C: ongoing interaction with extended circumstellar material with silicate dust
• Dark dust II: Properties in the general field of the diffuse ISM
• The spatial extent of Polycyclic Aromatic Hydrocarbons emission in the Herbig star HD 179218
• From Dust to Nanodust: Resolving Circumstellar Dust from the Colliding-Wind Binary Wolf-Rayet (WR) 140
• Constraining properties of dust formed in Wolf-Rayet binary WR 112 using mid-infrared and millimeter observations